1. Field of the Invention
The invention relates to a preparation for shrink-proofing wool.
2. Description of the Prior Art
It is well known that wool, when washed in the untreated state in aqueous liquors, shrinks and felts. In order to counteract this shrinkage and felting, chemical treatments which change the structure of the wool or finishes containing resin, which is deposited on the surface of and envelops the wool fibers, have been used. Each of these processes, however, provides products which the consumer finds have an uncomfortable "handle".
It has also already been recommended that the shrinkage of wool on washing may be reduced by treatment with organosilicon compounds. Such processes are described in British Pat. Nos. 594,901, 613,267 and 629,329. In accordance with these processes, the wool is treated with certain silanes.
A process is described in British Pat. No. 746,307 for preventing the shrinkage of wool by finishing the wool fibers with particular organopolysiloxanes. A certain degree of shrinkproofing is achieved by this procedure. However, the effect is not washfast.
In another series of publications, for example, German Offenlegungsschriften Nos. 22 42 297; 23 35 751; 25 23 270, processes are described for shrinkproofing keratin fibers by applying organopolysiloxanes which contain a specific amino group content as an essential characteristic. For example, the process according to German Offenlegungsschrift No. 22 42 297 is characterized by the fact that, as the organopolysiloxane, a material is used having units of the following general formula EQU R.sub.n SiO.sub.(4-n)/2
in which
n has an average value of 1.9 to 2.1 and PA1 R represents an organic residue, attached to silicon by a silicon-carbon bond, 0.25 to 50% of the R substituents being monovalent residues with fewer than 30 carbon atoms which, at a distance of at least 3 carbon atoms from the silicon atom, contain at least one amino group and at least one primary or secondary amino group --NX.sub.2, in which X is a hydrogen atom, an alkyl group with 1 to 30 carbon atoms or an aryl group, the remaining R substituents being monovalent hydrocarbon residues, halogenated hydrocarbon residues, carboxyalkyl residues or cyanoalkyl residues with 1 to 30 carbon atoms, of which at least 70% consist of monovalent hydrocarbon residues with 1 to 18 carbon atoms. PA1 R represents a monovalent group formed from carbon, hydrogen, nitrogen and, optionally, oxygen, which contains at least two amino groups and is attached to silicon by a silicon-carbon bond, PA1 R' represents an alkyl group or an aryl group, PA1 X represents alkoxy groups with 1 to 4 carbon atoms inclusive, wherein PA1 n is zero or 1 and/or X is a partial hydrolysate and condensate of the organosilane. PA1 R" is a lower alkyl residue with 1-7 carbon atoms, PA1 n is a whole number not less than 2, PA1 p is 0, 1 or 2, PA1 m is 0, 1 or 2, PA1 the sum of m+p has a value from 0 to 2, PA1 x is a whole number not less than 1, PA1 y and z each are 0 or a whole number with the proviso that when PA1 (aa) 90 to 99.9 mole% of units having the formula EQU R.sub.n SiO.sub.(4-n)/2 I PA1 in which PA1 (ab) 0.1 to 10 mole% of units having the formula EQU R'SiO.sub.3/2 II PA1 in which R' is an alkyl residue and/or a mercaptoalkyl or mercaptoaryl residue and/or O.sub.0.5 and/or a hydrogen residue,
A process for treating keratin fibers is known from German Offenlegungsschrift No. 23 25 751, which is characterized by the fact that the organopolysiloxane composition contains the product obtained by mixing (A) and (B), where
(A) is a polydiorganosiloxane with terminal hydroxyl groups attached to the silicon atoms and a molecular weight of at least 750, and wherein at least 50% of the organic substituents of the polydiorganodisiloxane are methyl groups and the other substituents represent monovalent hydrocarbon groups with 2 to 30 carbon atoms; and
(B) is an organosilane of the general formula EQU RSiR'.sub.n X.sub.3-n
in which
It is stated in this German Offenlegungsschrift that the two components of the mixture must be reacted if they are to be applied from an aqueous medium. Practical experiments have shown, however, that it is impossible to prepare stable aqueous emulsions from such reaction products. The reaction products formed are gel-like and cannot be converted to the emulsion form. They are, therefore, not suitable for making wool shrinkproof.
If these reaction products are used in the form of organic solutions, it turns out that the shrinkproofing effect is so slight that they cannot be used successfully in practice. Moreover, the moisture in the air causes a siloxane gel to separate out from the liquor containing the solvent after some time. This siloxane gel clogs up the equipment used for treating the wool.
German Offenlegungsschrift No. 17 69 249 teaches another process for treating fibrous material, e.g., wool, according to which organosiloxanes, containing mercaptopropyl groups, are used in emulsion form. With these compounds, however, it is only possible to decrease the soilability. The compounds are not suitable for making wool shrinkproof.
Furthermore, a hair treating material is known from German Offenlegungsschrift No. 16 17 443, which is based on organosilicon compounds and characterized by containing an organosiloxane copolymer of the general formula ##STR1## in which R is an alkyl residue with at least 8 carbon atoms,
y=0, p is at least 1 and in the case that PA2 z=0, m is at least 1 and x is greater than the sum of y+z. PA2 R is a methyl residue, up to 10 mole% of which, however, may be replaced by alkyl residues with a longer chain length or by aryl residues and up to 5 mole% of which may be replaced by mercaptoalkyl or mercaptoaryl residues, PA2 n has a value of 1.8 to 2.0, and
These compounds are also not suitable for shrinkproofing wool. Thus, these disclosures do not suggest the structure of an organopolysiloxane which would be suitable for shrinkproofing wool.